Question

A train covered k km at 40 kmph and another 2k km at 20 kmph. Find the average speed of the train in covering the entire 3k km ?

Answer 1

Hi there!
Here's the answer :

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¶¶¶ POINTS TO REMEMBER:

• $Speed = \frac{Distance}{time}$
=> $time = \frac{Distance}{time}$

• $Average Speed = \frac{Total\: Distance\: Covered}{Total\: Time\: Taken}$

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¶¶¶ SOLUTION:

Given,

A train covered k km at 40 kmph and another 2k km at 20 kmph

Total Distance covered = k + 2k = 3k

Time taken for total distance covered by train = $\frac{k}{40} + \frac{2k}{20}$

= $\frac{5k}{40}$

= $\frac{k}{8}\: hours$

Average speed of the train in covering the entire 3k km:

Avg Speed = $\frac{3k}{\frac{k}{8}} = 24\: kmph$

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